Typical disk drive systems include suspensions for supporting a transducing head over information tracks of a rotatable disk. Typically, suspensions include a load beam or suspension having a mounting region on a proximal end, a flexure or gimbal on a distal end, a relatively rigid region adjacent to the flexure, and a spring region between the mounting region and the rigid region. An air bearing slider which holds the transducing head is mounted to the flexure. The mounting region is typically attached to a base plate for mounting the load beam to an actuator arm. A motor which is controlled by a servo control system rotates the actuator arm to position the transducing head over the desired information tracks on the disk. This type of suspension may be used with both magnetic and non-magnetic disks.
FIG. 1 shows a top view of a known disk drive actuation system 10, for positioning a transducing head (not shown) over a track of a magnetic disk. The actuation system 10 includes, as shown from left to right in FIG. 1, a voice coil motor (“VCM”) 12, an actuator arm 14, a load beam or suspension 16, a flexure 18, and a slider 20. The slider 20 is connected to the distal end of the suspension 16 by the flexure 18. The load beam 16 is connected to the actuator arm 14 which is coupled to the VCM 12.
As shown on the right-hand side of FIG. 1, the disk drive assembly includes a disk 22 having a multiplicity of tracks 24 which rotate about an axis 26. During operation of the disk drive assembly, the rotation of the disk 22 generates air movement which is encountered by the slider 20. This air movement acts to keep the slider 20 aloft a small distance above the surface of the disk 22 allowing the slider 20 to “fly” above the surface of the disk 22. Any wear associated with physical contact between the slider 20 and the disk 22 is thus minimized.
As shown in FIG. 2, the flexure 18 provides a spring connection between the slider 20 and the load beam 16. Flexure 18 is configured such that it allows the slider 20 to move in pitch and roll directions to compensate for fluctuations in the spinning surface of the disk 22. Many different types of flexures 18, also known as gimbals, are known to provide the spring connection allowing for pitch and roll movement of the slider 20 and can be used with the present invention.
The VCM 12 is selectively operated to move the actuator arm 14 around an axis 28 thereby moving the load beam 16 and positioning the transducing head carried by the slider 20 between tracks 24 of disk 22. Proper positioning of the transducing head is necessary for reading and writing of data on the concentric tracks 24 of the disk 22. For a disk 22 having a high density, however, the VCM 12 lacks sufficient resolution and frequency response to position the transducing head on the slider 20 over a selected track 24 of the disk 22. Therefore, a higher resolution microactuation system is often used.
The density of concentric data tracks on magnetic disks continues to increase (i.e., the size of data tracks and radial spacing between data tracks are decreasing). In addition, the linear density continues to increase, which in turn increases the area bit density in both directions and reduced the area per magnetic bet cell. As the area per bit cell is reduced, the number of grains or particles per bit cell is also reduced unless the grain size is also reduced. The signal-to-noise ratio is a function of the number of grains per bit cell, so as this density increases, it becomes more difficult to write data to the tracks without affecting adjacent tracks. One technique in the art for enabling precise data writing is to use thermally-assisted laser writing. This technique requires the presence of a thermal energy source, such as a light beam (e.g., a laser beam) at or near the location of the transducing head. This thermal energy source provides energy to the recording medium, which reduces the medium's coercivity to facilitate the write process.
Accordingly, there is a need in the art for an optical path or waveguide for directing light from a top surface of a slider down to a point near the write gap of the magnetic recording head. There is a further need for a system for directing a laser beam to a position near the transducing head and onto the recording medium.